Method of and apparatus for generating holes in metal.



H. E. WARREN.

METHOD OF AND APPARATUS FOR GENERATING HOLES IN METAL. APPLICATION FILED AUG. 24 1 9 1 4.

1 1 28,045. Patented Dec. 29, 1914.

ED STAES ATENT oration.

HENRY ERNEST WARREN, or LANCASTER, PENNSYLVANIA, ASSIGNOR To MAC-IT PARTS COMPANY, E LANCASTER, PENNSYLVANIA, A ooRPoRATIoN 0E PENNSYL- dtl VANIA.

METHOD OF. AND APPARATUS FOR GENERATING HOLES IN METAL.

Specification of Letters Patent.

Patented Dec. 29, 19141:.

Application filed August 24, 1914. Serial No. 858,241.

certain new and useful Improvements in Methods of and Apparatus for Generating Holes in Metal; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable othersskilled in the art to which it ap- -pertains, to make and use the same.

The present invention relates to a method of and apparatus for generating-holes in metal, and more particularly to a method of and apparatus for generating hexagonal holes in set screws better known as hex-hole set screws.

The object of the invention is to produce amethod of and apparatus for generating holes in metal and more particularly for generating hexagonal holes in set screws.

The invention consists in the method and apparatus hereinafter described and particularly defined in the claims.

In the accompanying drawings illustrating more or less diagrammatically an apparatus for carrying out this method, Figure 1 is a plan of the machine; and Figs. 2, 3 and 4: illustrate the action of the tool on the stock.

Ihe stock S is a long bar supported in the hollow lathe spindle 1 of the head ,stock H of the machine, being held by-the 'Qhuck C in position for the performance upon it of the operation of making a set Screw. It has not been considered necessary to illustrate an automatic screw machine in which, this invention is particularly adapted to be used, such machine being. well known to those skilled in the art; it will accordinglysuffice for the purpose of explaining the method afid apparatus, to illustrate a simple form 0 mechanism as an embodiment of the apparatus forming the subject of this invention.

Preliminary to the operation of generating the hexagonal hole a round hole is bored in the end of the stock. The hole generating tool 2 has a shank 3 which is mounted in the spindle 4 supported in the journal 5 in turn supported upon the slide 6 of the machine. This slide 6 can be moved back and forth in the line of the axis of the head stock of the lathe by means of the handle 10 or the feed screw 11. The tool spindle 4 is arranged at an angle of about L} degrees to the axis of the head stock of the lathe,

and at its rear end it is connected by means of a universal joint 12 with the tool driving shaft 13. (In the drawing this angle of offset which is varied according to varying conditions is shown greatly exaggerated for the sake of clearness.) The tool spindle is provided with a gear 14 meshing with a gear 15 on the back shaft 16 of the machine; and on the lathe spindle is mounted a gear 17 meshing with the gear 20 on the back shaft 16. The gears 17 and 20 are of the .same size and the gears 14 and 15 are of the same size, consequently the tool spindle rotates at the same speed as the lathe spindle.

Power may be appliedtothe lathe spindle 5 by any suitable manner, as by means of a motor or belting. The backshaft 16 is connected by means of the gears 21 and 22 with a nut on'the feed screw 11. The lathe spindle and the tool spindle must be rotated at the same Speed (when the method requires the rotation of both) and they ,may be rotated, in either direction. It is immaterial in which direction the tools revolve so far as the carrying out of the invention is concerned. In the illustrated embodiment of the invention a truncated regular hexagonal pyramid constitutes the hole generating tool 2 whose cutting edges are formed by the intersection of the larger' base with the sides of the pyramid. These cutting edges perform the cutting operation in generating the polygonal hole in the stock. The tool is joined by its smaller base with the tool stock 3. Now, when the Stock S and the hole generating tool 2, are rotated at the same speed or by power, in the direction of the axis of the Stock, the cutting edges of the hole generating tool are forced into, the metal of the stock and generate therein a hole which, in the case under consideration, is a regular hexagonal prism. After. the operation and the tool is fed gradually either by hand of forming the hexagonal hole in the end of the stock, if the stock is to be used in the manufacture of set screws the exterior of the stock will be screw-threaded, and then the set screw will be cut off from the stock and the point shaped in any usual manner.

The present invention is broad and genpenetrate the stock. For example, as the point 30 on the tool 2 moves from the position shown in Fig. 2 to the position indicated in Fig.3, it will have moved axially a distance in the direction of the axis of the stock equal to the distance between the horizontal projection of the point 30 on the axis of the stock; but inasmuch as the tool and stock are rotating at the same speed, there will be no relative rotary motion between the two, only an endwise or axial motion. This is the cutting motion. When the point 30 travels from its position in Fig. 2 to its position in Fig. 3, the cutting edge 29-30 will have performed its cutting operation. It is then withdrawn from cutting action until point 30 again reaches its position as indicated in Fig. 2. The other cutting edges of the tool are brought into and withdrawn from cutting operation in exactly the same manner. It is apparent, therefore, that the feeding of the hole generating tool into the stock causes progressive cutting or shearing of the stock by the tool.

I am aware that prior to my invention hex-holes have been broached in metal by forcibly thrusting into it a tool moving in the direction of the axis of the hole to be shaped by the broaching operation, but in such operation there was no progressive action of the tool upon the metal except that due to the forcible thrusting of the tool into the metal; whereas in -the method of the present invention the cutting operation is a progressive operation which forms the hole in the metal as the material and tool rotate, thus avoiding subjecting the parts of the machine to the great stresses incident to broaching. Moreover the method of the present invention is susceptible of being carried on at a very high rate of speed, so that economy of operation is secured, both by reason of the great speed at which it may be carried on, and by reason of the uniformity of the power consumption during the carrying 'on of the operation.

The principal use now known for the method 'and apparatus of this invention is the manufacture of hex-hole set screwsfbut it is apparent that the invention contemplates, generically, the method of and machine for generating holes which consists in supporting the stock and tool at an angle to each other and in causing the stock and tool to rate the one with relation to the other 'an to move progressively toward each other. For example, regular or irregular polygonal or holes otherwise shaped may be generated by this method and machine, also holes having a portion consisting of a curved surface and portions consisting of prismatic surfaces may be made. The operation of the hole generating tool in forming the hole in the stock being operated upon is a progressive shearing action due to the inclination of the cutting face of the tool to the stock being operated upon by it.

Having thus described the invention, what is claimed is y 1. The method of generating holes in stock which consists in rotating the stock to be operated upon and the tool; operating upon the stock at the same speed with their axes at an angle to each other and intersecting and moving the tool and stock relatively to each other so as to cause the tool to enter the stock to generate a hole in the stock corresponding in form and size to the form andsize of the end of the tool, substantially as described.

2. An apparatus for generating holes in stock having, in combination, means for supporting and rotating the stock, means for supporting and rotating a tool for operating on the stock at the same speed of rotation as the stock, the axis of the supporting means for the stock and the axis of rotation of the tool being at an angle to each other and intersecting each other, and means for feeding the tool into the stock, substantially as described.

3. The method of generating holes in stock which consists in removing the greater portion of the material from the space to be bounded by the finished hole, in supporting the tool and stock with relation to each other so that the axis of the proposed hole intersects the face of the cutting tool and in causing the tool to move in a direction parallel to the said axis and in addition to cause successive portions of the edge of the cutting g1'essively toward each other, substantially as described.

5. The method of generating holes in stock which consists in supporting the stock to be operated upon in suitable position and subjecting it to the Operation of a tool, the toward each other during the operation, substock having the axis of the hole to be stantially as described.

formed therein arranged at an angle to the HENRY ERNEST WARREN. axis of the cutting portion of the tool, and Witnesses: 5 ca'using the stock and tool to gyrate the one HOMER B. LUTz,

With relation to the other and to move BERTHA ERK. 

